Drillable packer



June 28, 1960 Filed July 2, 1956 R. C. DAVlS ETAL DRILLABLE PACKER 3Sheets-Sheet 1 INV'ENTORS Ray C Dav/5 Poland 0. (0X Jahn J. LaneATTORNEYS June 28, 1960 R. c. DAVIS EI'AL 2,942,655

DRILLABLE PACKER Filed July 2, 1956 3 Sheets-Sheet 3 as :i 52

4 29 m INVENTORS Ao/cma 0. Cox

John J. lane United States Patent DRILLABLE PACKER Roy C. Davis, Roland0. Cox and John J. Lane, Dallas, Tex., assignors, by mesne assignments,to The Guiberson Corporation, Dallas, Tex., a corporation of Texas FiledJuly 2, 1956, Ser. No. 595,455

3 Claims. (Cl. 166-124) This invention is concerned with a well packerwhich is employed for closing off a well pipe or for sealing the annularspace between a well casing and a tubing or other pipe extending intothe casing, for producing .oil or gas from a strata below the packer, orfor the purpose of carrying out various well operations, such ascementing, acidizing, or otherwise treating the producing formation orformations of the well.

This invention is particularly concerned with improvements in that typeof well packer known as a drillable packer wherein all parts are made ofdrillable material so that it can be drilled up by the drill bit forremoval, but it will be understood that the improvements described andclaimed can be employed in any well packer of the type herein described,whether it be drillable or not.

Well packers of the type designed to be run and set in the casing areusually provided with a sleeve of elastic material, such as natural orsynthetic rubber, which is slidably mounted on a tubular support ormandrel. Segmented, toothed slips are provided at each end of the packersleeve which co-act with conical expander heads to expand the slips intoengagement with the casing to form an anchor, and to compress and expandthe packer to seal the annulus. The conical expander heads are attachedto, or are in contact with, the rubber sleeve, and as the lower slipsare moved upwardly along the casing wall they push the lower expanderhead upwardly against the packer sleeve, causing the resilient packersleeve to be shortened and expanded radially into sealing engagementwith the casing wall.

In prior packers of this type the force for expanding the packer sleevehas been applied by upward pull applied to the lower slips, which arecarried on a base shoulder attached to the running tool, and such forcewas indirectly applied to the packer sleeve through the expander head.Such arrangement resulted in a great loss of force by reason of the factthat the greater amount of the force applied was dissipated in draggingthe toothed slips along the wall of the casing a sufiicient distance tomove the lower expander head upwardly enough to adequately expand thepacker sleeve into sealing engagement with the casing. It has beenestimated that at least 60% of the force applied by upward pull wasdissipated in dragging the slips along the casing wall. Thisnecessitated increased upward movement of the tubing in order to set thepacker, which is particularly disadvantageous in deep wells Where theamount of upward movement of the tubing is limited by reason of thestretch of the tubing and in many instances resulted in aninsufliciently expanded packer. Such increased pull resulted in addedstrain on the derrick, pipe and surface equipment, and the operatorcould never be certain that the packer was sufliciently expanded to forma proper seal.

Another defect in such prior packer devices was that the segmented slipsdid not move upwardly into engagement with the casing uniformly so thatthey were not evenly spaced and in peripheral alignment under thepacker, causing the packer to be off center, resulting in unevendistribution of the rubber material of the packer in the annulus whenexpanded, and a poor seal.

Still another problem with such prior packers was that the lowerexpander head and slips were attached to the mandrel, and prevented frommoving upwardly thereon, solely by shear pins, with no positive means toprevent the expander head and slips from being disengaged from themandrel and allowed to move upwardly while being run, often resulting inpremature setting of the packer.

In such prior packers the running tool, is threadedly engaged with thepacker mandrel by left hand threads so that after the packer is set therunning tool can be disengaged by right hand rotation of the tubing.Heretofore no positive means has been provided for preventing therotation of the mandrel while the running tool is being unthreadedtherefrom.

This invention is intended to overcome the abovementioned problems andothers.

It is, therefore, a primary object of this invention to provide a wellpacker wherein substantially all -of the force applied by upward pull onthe running tool .is applied directly to the lower expander head andtherethrough to the packer sleeve.

Another important object is to provide means ina well packer foruniformly moving the lower slips into engagement with the casing,whereby they are in peripheral alignment under the packer. I i

A further object of this invention is to provide positive means in awell packer for preventing the lower expander head from moving upwardlyto prematurely set the packer while the packer is being run.

A still further object is to provide means in a well packer topositively hold the packer mandrel against rotation while the runningtool is being rotated free of the mandrel after the packer has been set.

Still another object is to provide positive means in a. well packer toprevent upward movement of the upper expander head of the packerassembly, while the packer is being run, to prevent premature setting oftheupper slips.

Another object is to provide a shoulder on the packet mandrel whichmoves upwardly in the packer sleeve, when expanded, to form a recessbetween the shoulder and the lower expander head, in which the rubber ofthe packer sleeve may flow when the packer is expanded, to therebytransfer force, applied from above, directly to the packer, after it isset, to increase the sealing effect thereof.

A still further object is to provide a packer assembly wherein the upperslips are set before the lower slips to provide a firm anchor forsetting the lowerslipsand expanding the packer sleeve.

Other and further objects of this invention will become apparent uponreading the following detailed specification, and by referring to thedrawings annexed hereto, and made a part hereof.

A preferred embodiment of the invention is shown in the attacheddrawings in which,

Figures I and II are a partially sectionalized, eleva' tional view of awell packer assembly incorporating the improvements constituting theinvention, showing the packer assembly and attached to the running toolas they would be assembled for lowering into the casing on a tubingstring.

Figure III is a partially sectionalized, elevational view of the packerassembly after the running tool has been disengaged from the anchor cageand drawn upwardly to set the upper slips.

Figure IV is a partially sectionalized, elevational view of the packerassembly after the running tool has been further drawn upwardly to shearthe upper and lower expander heads fiom the mandrel and the lower slipsfrom thelo'wer expander head to permit the spring urged pins underneaththe lower slips tomove said' slips up wardly intoengagement with thecasing.

V .Figure V is a partially sectionalized, elevational view packersleevehas been expanded intoengagement with the casin V Figure V1 is apartially sectionahzed, elevationalview tfthe packer assembly after thepacker sleeve has been fully expanded into sealing engagement with thewall of meaning. i

' a Figure VII isa sectionalized, elevational view of the packerassemblyafter the running tool has been disengaged therefrom andwithdrawn.

the body 32. I The longitudinal movement of therings p Figure VIII is apartially sectionaliz ed,,elevational view 7 of the packer assemblyafter the running too] has been reinserted subsequent to attaching a'tailpipe, crossover V apparatus or other well producing or treatingapparatus.

ln. the drawings numeral references are employed to designate thevarious parts, and like numerals indicate like pants throughoutthevarious figures of the drawings.

flackers of the typeshown herein are customarily lowered into the wellcasing, .disengageably'attached to a tool which issuspended to a stringof pipe, extending from the earths surface.

Figures I and II show the packer assembly, attached to the running tool,as it would be assembled for lowering intothe casing. The packer isrelaxed and run' with clearance, except for the drag of the spring urgedfriction pads 34 on the anchor cage 31.

The sub 10 is interiorly threaded at its. upper end, as

indicated at 11,10 permit the threaded engagement of the sub with atubing string (not shown), extending'from the earths surface.v uppertubular member 12 'is threadedlylengaged to the sub 16 by righthand'corn p'anion threads 13. The adaptor coupling 14 is threadedlyconnected to the tubular member 12 by right hand companion threads 15and to the packing tube 16 by fight hand companion threads 17.

An annular outwardly extending flange 18 is formed on the upper end ofthe adaptor coupling 14, and a resilient sealing ring 19 is disposedabout the flange 18 to jform a seal between the inner surface oftheupper ex- 3 pander head '49 a d the fla ge i A seal retainingabuttment collar 20 is afiixed' about 7 the packing tube'16 by means ofwelding, or otherwise,

and an upper' set 21 and a lower set 22 of V- type packing rings, whichare separated by a spacer ring 23, are disposed between the abutmentcollar 20 and the'upper end ofthe coupling 24.' The packing rings 21 and22 are turned in Opposite directions, and provide a fluid seal betweenthe pa king mandrel 53 and the packing tube 16 when the running tool isdisposed in the mandrel.

V The coupling .24 is threadedly engaged to'the lower end, of thepacking tube 16 by right hand companion threads 25'and to the upper endof the lower tubular sect on' or shi tinsp uc i no w e v n toolstherebelow.

. The anchor .cage assembly 31 includes a tubular body '32, which isthreadedly engaged 'to 'the'sub 10 by buttress threads 33, which areleft hand threads, to permit disengagement of the sub 10 from the anchorcage body byright hand rotation of the tubing string.

. Aplurality of spring urged friction pads 34 are carried about theanchor cage body 32 and are urged into engage ment with the wall'of thewell 36 by the springs 35. The

outward movement of the friction pads 34 is limited'by 7 upper and lowerlimit rings 37 and 38, disposed about 37 and 38 is limited by the upperand lowerlimit shoulders 39 and 40, provided on the body v32.

A plurality of upper slip segments 42, having peripheral teeth 43thereon, are spaced aboutthe lower end of the anchor cage body 32, saidslip segments 42 being disengageably interlocked with the body 32 bymeans of the interlocking shoulders 44 a nd.45, provided on the body 32and the slips '42. -A.garter spring 46 is stretched about'the lower endsof the slips'42 to hold the slips in engagement with the upperexpanderhead '49.

The slip segments 42 have interior, .tapered surfaces 47 facingdownwardly, which are in contact with, and co-act 'with, acorresponding, upwardly facing, tapered outer surface 50 on the upperexpander head 42. The surfaces 47 and co-act to move the slip segments42 outward- .ly'into engagement with the casing, when the expanderrunning tool in the event the shear screws ,52 should becomeaccidentally broken while lowering the packer in the'well casing. .Thispositively prevents the premature expansion andsetting of the upper slipsegments 42;

A' plurality of shear screws 52 frangibly connect the upperiexpanderhead 49 with the packer mandrel 53. The tubular packer mandrel 53 isthreadedly connected to the adaptor coupling 14 by means Of buttressthreads 54; The threads 54 are left hand threads so that the adaptorcoupling may be disconnected fromthe mandrel 53 by right hand rotationof the tubing string, and such threads 54 are preferably buttressthreads sothat they willsupport the axial'load of setting and expandingthepacker by upward pull on the tubingstring; l i

A base ringSS, forming an upwardly facing annular shoulder 79, isthreadedly connected to the mandrel 53 7 tends into the key channel 58.The key screw 59 is free to move longitudinally'in the key channel 58but prevents relative rotation between the expander head 49 and themandrel 53.

As shown in Figure I, the key screw 59 is at the upper limit of the keychannel 58, wh'en the packer is assembled in relaxed position forrunning. 'Thus the key, screw 59 prevents upward movement of theexpander head 49 with relation to the mandrel to further safeguardagainst premature setting of the upper slips 42, in the event the shear'screws52 should become accidentally broken while the packer is beingrun The keyscrew59 also holds the mandrel 53 against rotationafter-theupper slips 42 are. set, to permit the threads '54 to be disengaged byright hand rotation of the tubing string, as will be hereinafterexplained. The key channel 58 is long enough to' permit the key screw 59to move downwardly therein sufficient distance to allow the packersleeve to be fully expanded and set (see Figures VI and VII). i V I Aconventional junk pusher 60 is threadedly engaged to the lower end ofthe'base ring 55 by right hand com panion threads 61. A resilientsealing ring 62 is disposed between the base ring 55 and the junk pusher60, said resilient sealing ring having a tapered outer face 68 thereonarranged to form a sealing surface for the V tapered sealing face 67 onthe fiapper'valve 65.

The disc-shaped flapper valve 65 is of conventional construction and isspring urged inwardly by a coil spring (not shown) disposed about apivot pin 66, by which the flapper valve is pivotally attached to thejunk pusher.

The tubular member 26, extending through the packer assembly, holds theflapper valve 65 open, while the packer is being run, but when thetubular member 26 is withdrawn, the flapper valve 65 is permitted toclose, by spring action, and the conical seating surface 67 thereoncomes into contact with the sealing ring 62 and closes and seals theaxial passage through the packer, thereby confining fluid pressure belowthe packer. When pushed open, the flapper valve 65 may extend into acircular passage 69 provided in the wall of the junk pusher 60.

The junk pusher 60 has a plurality of flow apertures 64 through the wallthereof to permit displacement of fluid therethrough as the packer islowered in a column of fluid in the casing. An enlarged lower rim 63 isprovided on the junk pusher 60 to push debris and other obstructions inthe well fluid ahead of the packer, as it is lowered into the casing, toprevent such foreign material from coming in contact with the lowerslips 75 and expander head 72, and from becoming lodged about the packersleeve.

The lower expander head 72, when assembled, as shown in Figure Ii, isabutted against an external, downwardly facing, annular shoulder 73,formed on the mandrel 53.

The lower expander head 72 has an external, tapered, downwardly facingsurface 74 thereon which is arranged to co-act with corresponding,internal, upwardly facing, tapered surfaces 77 on the lower slipsegments 75. The plurality of slip segments 75 have peripheral teeth 76on the outer surfaces thereof arranged to penetratingly engage the wallof the casing 36 when the slips 75 are expanded by sliding coactionbetween the tapered surfaces 74 and 77.

The tapered surfaces 74 and 77 on the expander head 72 and slip segments75 are placed in coinciding relationship, with the expander head 72abutted against the shoulder 73, and the slip segments 75 abuttedagainst the upper face 79 of the base ring 55. After being sopositioned, the expander head 72 and slip segments 75 are frangiblyconnected together, and to the mandrel 53, by shear screws 80. A garterspring 78 is extending about the slip segments 75 to hold them inengagement with the expander head 72, afterthe shear screws 80 have beenbroken, in the manner which will be hereinafter described.

The shoulder 73 positively prevents the upward movement of the expanderhead 72, with relation to the mandrel, while the packer is beinglowered, which prohibits the premature expansion of the packer shouldthe lower slip segments 75 become accidentally sheared from the expanderhead 72. The shoulder 73 has another important function which will behereinafter explained.

A vertical bore 83 is formed in the base ring 55, under each slipsegment 75, and a coil spring 84 is disposed in each said bore with thelower end thereof resting on the upper face of the junk pusher 60. A pin85, having an enlarged head 86 thereon, is movably disposed in each bore83, and the upper end of said pin slidably extends through a guide hole87, formed through the upper face of the base ring 55. The spring 84contacts the enlarged head 86, and normally urges the pin 85 upwardlyand outwardly of the base ring 55, but when the packer is assembled thepin 85 is retracted, in the base ring 55, against the spring 84. Theslip segments 75 are abutted against the upper face 79 of the base ring55 and fixed to the expander head 72,as hereinbefore explained, tothereby retain the pins 85 in retracted position, while the packer isbeing lowered, as shown in Figure II. The pins 85 remain in retractedposition until the shear screws 89 are broken, at which time the springs84 relax and cause the pins 85 to push the slips 75 upwardly intoengagement with the casing, as hereinafter explained.

An elongated tubular packer sleeve 90, which is made of resilientmaterial, such as a natural or synthetic rubber compound, is slidablydisposed about the mandrel 53, so that it is arranged to slide on themandrel and be shortened and radially expanded between the expanderheads 49 and 72, as the lower expander head 72 is moved upwardly byupward pull on the tubing string, after the slip segments 42 and 75 havebeen set against the wall of the casing 36, in the manner hereinafterdescribed.

An upper retainer ring 91, made of relatively soft material, such aslead alloy, is disposed between the upper end of the packer sleeve 90and the upper expander head 49, and a lower retainer ring 92, made oflike material, is disposed between the lower end of the packer sleeve 90and the lower expander head 72. The rings 91 and 92 are arranged toexpand upon contraction and expansion of the packer sleeve to preventthe resilient material of the packer. sleeve from flowing about theexpander heads 49 and 72.

The well packer assembly, illustrated in the drawings, can best beunderstood by considering the operation and function thereof, which isdescribed as follows:

The packer is assembled and attached to the running tool in the mannerillustrated in Figures 1 and II. The sub 10 is then attached to a tubingsection and the tubing string is progressively made up by joiningsuccessive joints as the packer assembly, mounted on the running tool,is lowered into the casing 36.

The running tool is made up of the sub 10, the upper tubular member 12,the anchor cage 31, the adapter coupling 14, the packing tube 16, thecoupling 24 and the lower tubular member 26. The running tool may bedisengaged and removed from the packer after the packer is set in thecasing.

It will be noted that all parts of the packer assembly are rigidlyattached to, and carried by, the running tool as it is lowered into thecasing. The junk pusher 60 is rigidly attached to the mandrel 53,through the base ring 55, and the mandrel is in turn secured to therun-, ning tool by the threads 54 on the adaptor coupling 14. Throughthe adaptor coupling 14, the tubular member 12 and the sub 10, themandrel 53 is secured to the tubing string. Therefore, any impact ordrag encountered by the junk pusher 60, while the packer is beinglowered,

will be transmitted to the running tool and therethrough to the tubingstring, thereby eliminating the possibility of the mandrel 53 movingupwardly to prematurely set the packer.

The lower slip segments 75 are held in retracted position under theexpander head 72 by means of the shear screws which pass through theslip segments 75 and expander head 72 into the wall of the mandrel. Theshear screws 80 prevent the slip segments 75 from moving upwardly alongthe outer face of the expander head 72 and they are prevented frommoving downwardly by the upper face 79 of the base ring 55. As sopositioned the slip segments 75 hold the follower pins in retractedposition.

The lower expander head 72is held in upward position by the shear screws80, and is prevented from moving upwardly with relation to the mandrel53 by the annular shoulder 73. Thus there is no possibility of thepacker becoming prematurely expanded while being run, because theexpander head 72 cannot move upwardly until the setting tool is releasedfrom the anchor cage 31 and pulled upwardly, as will be hereinafterdescribed.

The upper expander head 49 is held against downward movement by theshear screws 52 and against upward movement by the flange 18, which isin engagement with the upwardly facing shoulder 51, and by the key screw59, which is in engagement with the upper end of the key channel 58.

The upper slip segments 42 are held in retracted position against theexpander head 49 by the garter spring 46,

and are held against axial movement with relation to the a to beunscrewed from the mandrel.

packer assembly by the interfitting engagement between thejshoulders 44and 45 on the anchor cage body 32 and the slip segments 42,respectively.

The anchor cage assembly 31 is'disengageably at tached to the tubingstring by means of the left hand threads 33,. The upper slips '42 cannotbe expanded free of the anchor cage 31 and into engagement with the wallof the casing until the sub 10 hasbeen disengaged from the anohor cageby right hand rotation of the tubing string, to permitthe upperexpanderhead 49 to be raised.

and interact with the slips 42.'

, Therefore, it will be seen that all parts of the packer 7' '73.-Any'jar or-impact on the expander head 72 will be effectivelytransferred through theshoulder '73-and absorbed by the running tool andthe tubing string.

. When the packer assembly has been runto the desired depth where it isto be set, the tubing string isrotated to the right to disengage .thethreads 33. 'The friction pads 34are pressed against the wall of thecasing, and in'frictional engagement therewith, to sufficient extent tohold the anchor'cage body 32 against rotation to permit a the threads 33to be disengaged. After disengagement .of j the threads 33 the tubingstring may be pulled upwardly, thus moving ,the running tool upwardlywith relation to the anchor-cage 31, the friction pads 34 serving tohold the anchor cage against upwardmovement.

,As shown in Figure IH, theupward movement of the running tool, and thepacker assembly secured there to,

- causes theupper expander head 49 to slidably interact with theupperslip segments 42' and push the slips 42 out- 'wardly into anchoringengagement withthe casing 36. 'The interlocking shoulders.44 and 45 arefreed of engagement, permitting the anchor cage 31 to be withdrawn withthe running tool.

It will be noted that the threads 54, which are also "left 'handthreads, are not disengaged by this initial rotation of the tubingstring, because such threads 54 cannot be unscreweduntil after thethreads 33 have been disengaged and the upper expander head 49 has beenforced mtoftighhfrictional engagement with the ,upper slips 42* j andexpansion ring 91. Until the upper head49is thusheldagainst'rotatiomthere is no force for unscrewing the mandrel 53 fromthe adaptorcoupling 14. After the upper expander head 49 has beensecured against rotation,

the mandrel 53 is held against rotation by thekey screw '59 and the keyslot 58 olpermit the adaptor coupling 14 'After the upper slips 42 havethus been permanently set against: the wall of .the casing 3 6, furtherupward movement ofthe tubing string and the running tool will therraises the slips 75 above the lower end of the expander head 72 whichbrings thelower end of the expander head 72 into direct contact with theupper face of the base ring 55, as shown in Figure V. This causesfurther force-of upward pull on the tubing string to be applied directlyto the expander head 72 and therethrough to the packer sleeve 90;Simultaneously with this operation, the springs 84 are recompressed tosome extent as the slips 75 move upward into anchored engagement withthe casing. However, the springs 84 are strong enough to cause thefollower pins 85 to holdthe slip-s 75 upward above the lower end of theexpander head 72 while the head 72 is moved upwardly on base ring toexpand the packer sleeve 90;'as shown in Figures V and VI.

The resistance of the packer sleeve 90 causes the mandrel 53 to moveupwardly with relation to the expander head 72, thereby causing theshoulder 73 and head 72 to separate. The shoulder 73 thus moves upwardlyinto the body of the packer sleeve 90, and the resilient material of thepacker sleeve flows into the annular recess formed between such shoulderand the upper end of the expander head 72, as thepacker sleeve isexpanded as shown in Figure V.

Thus it will be seen that the entire force applied by upward pull on thetubing string is transmitted directly into expanding the rubber materialof the packer sleeve.

' end of expander head 72 at all times'as the expander head is movedupwardly to expand the rubber material of the packer sleeve. The springs84 and pins 85 move the lower slips 75 upwardly and maintain theminengagement with both the casing 36 and the lower expander head 72 as theexpander head is moved upwardly, but the slips are not used as a meansoftransmitting the setting force to the rubber material of the packersleeve. In other words, at all times while the compressive force isbeing applied to the rubber material of the packer sleeve the lowerexpander head 72 is in direct engagement with the base ring 55, carriedby the mandrel 53. Therefore, no force is wasted in dragging. the slips75 along the casing wall, becausethe slips are moved upwardly and heldin engagement with the casing 36 and expander head 72 by the resilientforce applied through the springs 84 and pin 85. r r

It has been found that where the lower slips are used as a means oftransferring the compressive force to the rubber material of the packer,as in previous packers, there is at least a loss of force by reason ofthe frictional drag between the slips and the casing wall. For instance,a 20,000 lb. pull on the mandrel 53 would resuit in approximately 8,000lbs. of actual compressive cause the shear screws 52, holding the upperhead 49 to the mandrel 53, to break. Such upward movement of runningtool also causes the shear screws 80, holding the lower slips 75 tolower head 72, and to the mandrel 53, to break,,seve ring the slips 75from head 72, and head 72 from mandrel 53. Thebreaking of the shearscrews,

7 52 and .80 permits the mandrel 53to move'upwardly with 'head 72 fromthe mandrel 53, the springs 84 relax, pushing the follower pins 85upwardly, simultaneously and 1 quickly moving the lower slip segments 75upwardly along the expander head 72 into uniform and aligned engagementwith the casing 36, as shown in Figure IV. e

Continued upward movement of the. tubing string,

7 carrying with it themandrel 53, and the base ring 55, furforce appliedto the rubber material: In using the present invention the full force ofpull applied to the'tubing string is transmitted directly to the rubber,material of the packer and there is no loss of force, thus resulting inshorten arid radially expand the packer sleeve, the key channel 58 hasmoved upwardly with relation to key screw 59, as shown in Figure VIbecause expander head 49 is held against upward movement by the setslips 42. Since the upper expander head 49 is now in tight compressiveengagement with the upper slip segments 42, it is held against rotationsufiiciently to hold the mandrel 53 against rotation through the keyscrew 59 and'key channel 58, to permit the adaptor ring 14 to beunthre'aded from the mandrel 53 to thereby free the running tool fromthe mandrel, and packing assembly, carried thereon.

The running tool, including the upper tubular member 12, the packingtube 16, with packing thereon, lower tubular member 26 and anchorcage31, may then be raised upwardly on the tubing string, leaving thepacker set in the casing (Figure VH), When the lower tubular member 26is removed the flapper valve 65 is free to move upwardly to closedposition as shown in Figure VII, to close and seal the axial passagethrough the packer assembly, to thereby confine fluid pressure below thepacker.

After the running tool has thus been removed from the packer the wellmay be conditioned by circulation of fluid through the tubing string, ifdesired.

Various types of production, flow control and well servicing tools canbe attached to the lower end of the running tool, either before thepacker is initially run into the well, or they can be attached, and runthrough the packer, after the packer is set. The axial passage throughthe packer is of such diameter as to permit such tools to freely passtherethrough. These devices may include seating nipple assemblies, tailpipes, perforated and plain production tubes, chokes, lead-in subs,crossover equipment and many others.

The running tool, suspended on a tubing string, and with a wellproduction or well servicing device attached to the lower end thereof,may be re-inserted in the packer as shown in Figure VIII, and provides aflow conduit through the packer which is sealed to the interior wall ofthe mandrel 53 by the sealing rings 21 and 22. The running tool may beheld down in the packer against pressure differential from below thepacker by weight applied to the tubing string at the surface.

Means could be provided for relatching the running tool in the packer,but same is not illustrated herein as it forms no part of the presentinvention.

After the running tool has been run back into the packer as shown inFigure VIII, any weight applied to the tubing string will be transmittedfrom the running tool to the mandrel 53 in downward direction, whichwill cause the mandrel to move downwardly through the rubber material ofthe packer sleeve 90. The shoulder 73, in effect, creates a differentialpiston which works against the fiowable rubber material, thus causingthe downward movement of the mandrel to result in increased pressure inthe rubber, which pressure is transmitted through the rubber to form atighter seal with the casing. Therefore, increased weight applied to themandrel is utilized in effecting a tighter seal, rather than weakeningthe seal, as would be the case if the shoulder 73 was not present.

Of course the packer could be used simply as a closure of the casing toconfine fluid and pressure below the packer, as shown in Figure VII.

The slips 42 and 75, the heads 49 and 72, the base ring 55 and junkpusher 60, are preferably made of drillable material such as cast iron,and the mandrel 53, all screws employed, and the flapper valve 65 arepreferably made of drillable material such as brass. The packer sleeve90 is preferably made of canvas reinforced neoprene, which is alsodrillable. Therefore, all components of the packer assembly, which isanchored in the casing, are made of material which can be readilydrilled up by the drill bit when it is desired to remove the packer.

It will thus be seen that there have been provided im provements in awell packer which insures against premature setting of the packer whileit is being run, which provides means for applying all setting forcedirectly to the packer sleeve, which assures suflicient expansion of thepacker to form a positive seal with less force, which has increasedsealing effect upon application of weight from above after setting,which provides a positive and simple means of disengaging the runningtool from the packer assembly after it is set, and other advantageshereinbefore mentioned.

It will be understood that only a preferred embodiment of the inventionhas been disclosed herein and that other and further forms andembodiments may be made and still remain within the spirit and scope ofthe appended claims.

We claim:

1. In a well packer, a mandrel; a base member carried by the mandrel; aplurality of lower slips abutting against the base member; a lowerexpander head; frangible means connecting the lower expander head to thelower slips and to the mandrel, the lower slips and expander head havingcontacting tapered surfaces thereon arranged to slidably co-act to movethe slips into engagement with a well casing; a resilient packer sleevedisposed about the mandrel above the lower expander head; an upperexpander head; frangible means connecting the upper expander head to themandrel above the packer sleeve; a plurality of upper slips; the upperslips and upper expander head having contacting tapered surfaces thereonarranged to co-act to move the slips into engagement with a well casing;a running tool extending through the mandrel and being threadedlyengaged therewith; an anchor cage threadedly engaged to the upper end ofthe running tool and being disengageably interlocked with the upperslips; the said upper slips being movable radially out of engagementwith the anchor cage by co-action with the upper expander head uponunthreading the running tool from the anchor cage and moving sameupwardly therethrough; an elongated vertical key channel in the outerwall of the mandrel; and a key attached to the upper expander head andslidably disposed in the channel to hold the mandrel against rotationwith respect to the expander head.

2. In a well packer, a mandrel; a base member carried by the mandrel; aplurality of lower slips abutting against the base member; a lowerexpander head; frangible means connecting the lower expander head to thelower slips and to the mandrel, the lower slips and expander head havingcontacting tapered surfaces thereon arranged to slidably co-act to movethe slips into engagement with a well casing; a resilient packer sleevedisposed about the mandrel above the lower expander head; and external,downwardly facing, annular shoulder on the mandrel initially positionedagainst the lower expander head but arranged to move upwardly in thepacker sleeve to provide an annular recess between the expander head andthe shoulder in which the resilient material of the packer sleeve mayflow when the mandrel is moved upwardly to expand the resilient packersleeve; the said mandrel being free to move downwardly with relation tothe lower expander head after the packer sleeve is expanded; an upperexpander head; frangible means connecting the upper expander head to themandrel above the packer sleeve; a plurality of upper slips; the upperslips and upper expander head having contacting tapered surfaces thereonarranged to co-act to move the slips into engagement with a well casing.

3. In a well packer, a mandrel; a base member carried by the mandrel; aplurality of spring urged members carried by the base, and beingnormally urged upwardly thereof; a plurality of lower slips abuttingagainst the base member and holding the spring urged members inretracted position; a lower expander head; frangible means connectingthe lower expander head to the lower slips and to the mandrel, the lowerslips and expander head having contacting tapered surfaces thereonarranged to slidably co-act to move the slips into engagement with awell casing; a packer sleeve made of resilient material disposed aboutthe mandrel above the lower expander head; an external annular shoulderon the mandrel initially positioned against the lower expander head butarranged to move upwardly in the packer sleeve to provide an annularrecess between the expander head and the shoulder in which the resilientmaterial of the packer sleevemay flow when themandrelis moved upwardlyto expand the packer sleeve; said mandrel'being free to move jdownwardly with relation to'the lower expander head after after :thepacker sleeve is expanded; an upper expander headrfrangible meansconnecting vthe upper 'ex- 7 pander head to the mandrel abovelthepackerlsleeve; a

plurality of npper slips; the upper slips and upper ex? pander headhaving-contacting tapered surfaces thereon arranged to co-act tomove-the slips into engagement with a well easing; the said springiirg'edmembers being are R'eferencesCited in the file of this patentUNITED STATES PATENTS Baker et a1 May 17, 1938 Ian; 16, 1940 Burt Boydet al. s Ian. 14, 1941 Bonner V ,May 1, 1951 Burns Mar. 18,1952,Morrisett V.. Mar. 18, 1952 Baker'et al. V May 27, 1952 Bream; June 17,1952 Lee June 15, 1954 Ragan et a1. i Nov. 23, 1954 Baker V V June '19,1956 luhvi

